Old/Newer Refrigerator/Freezer Efficiency Questions

[Birken Vogt]

Hi all,

I recently bought a c. 2002-2003 side by side Whirlpool Gold refrigerator w/ice to replace my c. 1985 plain jane top freezer model. That old one seemed to be a hog since I replaced a 1950s GE fridge, causing my electric bill to go up (but the GE was small and impractical any more for me.) The old fridge defrosted it seemed like 4 times a day with very little frost on the evap and just generally ran the compressor a lot, and it was loud too. The new one is much better all around but I haven't seen a bill yet.

I also got a freezer at the same place, new and old same vintage, 1985 to 2002, but the freezers apparently are made by Fridgidaire (new one Kenmore, old is Monkey Wards) and are almost identical in design and construction except the new one feels a bit flimsier inside and out and uses 134a instead of R12. They are upright models where the shelves get cold. So I am wondering here if there is possibly that much room for improvement, perhaps increased compressor/electric motor efficiency or better cabinet insulation?

Thanks for any thoughts.
Birken

[Going_Going_Gone]

We bought a new Energy Star rated refrigerator for our basement wet bar area last year. Old one was around 1988 vintage and was really struggling to fire up the compressor. Starting the next month, our electric bills dropped around $25/month year-round. I figure the new refrigerator will pay for itself in 3+ years. Next purchase will be high efficiency AC units

[mike1000001]

Originally Posted by Birken Vogt

Hi all,

I recently bought a c. 2002-2003 side by side Whirlpool Gold refrigerator w/ice to replace my c. 1985 plain jane top freezer model. That old one seemed to be a hog since I replaced a 1950s GE fridge, causing my electric bill to go up (but the GE was small and impractical any more for me.) The old fridge defrosted it seemed like 4 times a day with very little frost on the evap and just generally ran the compressor a lot, and it was loud too. The new one is much better all around but I haven't seen a bill yet.

I also got a freezer at the same place, new and old same vintage, 1985 to 2002, but the freezers apparently are made by Fridgidaire (new one Kenmore, old is Monkey Wards) and are almost identical in design and construction except the new one feels a bit flimsier inside and out and uses 134a instead of R12. They are upright models where the shelves get cold. So I am wondering here if there is possibly that much room for improvement, perhaps increased compressor/electric motor efficiency or better cabinet insulation?

Thanks for any thoughts.
Birken

Do you mean room for improvement like if you were to replace your 2002 models with new ones?
The answer is no. The only way you are going to beat the energy efficiancy with what you have now is to get a model with a variable speed compressor and the savings there may be $1 a month at best. Plus you'll have to hand out at least $2500 or so for one of those refrigerators.

[LMJD]

We've got an ancient Kenmore and a fairly new Maytag (?) running side by side in our basement. The new one runs WAY less that the old one and I'm convinced it's much more efficient. A couple years ago I put a new door seal on the old one, but it still cycles more often.

[drcampbell]

Fridges did become energy hogs in the 1970s and 1980s, the defrost cycle being one of the bigger consumers. Customer satisfaction was considered much more important than energy conservation, so overkill was common.

One relatively simple thing you can do with older fridges to reduce the energy consumed by defrosting is to connect the defrost timer to the compressor instead of the line. Then, instead of defrosting, say, once every 24 hours of real time, it'll defrost once per 24 hours of compressor run time, saving a whole lot of energy in winter, spring and fall, in the summer in moderate climates, and in air-conditioned houses.

Switching from fiberglass batt insulation to injection-molded polyurethane foam cut heat gain by about half. That mostly occurred in the 1990s.

There's still a lot of energy savings possible, but most appliances are marketed based on first cost, not energy savings. The SunFrost people provide the counter-example, using perhaps 1/10 as much energy as conventional fridges.
Sun Frost energy efficient refrigerators

[Birken Vogt]

Originally Posted by mike1000001

Do you mean room for improvement like if you were to replace your 2002 models with new ones?
The answer is no. The only way you are going to beat the energy efficiancy with what you have now is to get a model with a variable speed compressor and the savings there may be $1 a month at best. Plus you'll have to hand out at least $2500 or so for one of those refrigerators.

It hadn't really occurred to me to ask that question but I did notice that the models made today that are similar to mine seem to be almost identical. My main question was:

The 2002 upright freezer with the condenser in the outside walls and the evaporator-shelves seems almost identical to the 1985 one it replaced other than the R12/R134a. Do you think it can be much more efficient than the old one? I guess the variables are insulation (old one appears to be foam as well), refrigerant, motor, and compressor.

Originally Posted by drcampbell

Fridges did become energy hogs in the 1970s and 1980s, the defrost cycle being one of the bigger consumers. Customer satisfaction was considered much more important than energy conservation, so overkill was common.

One relatively simple thing you can do with older fridges to reduce the energy consumed by defrosting is to connect the defrost timer to the compressor instead of the line. Then, instead of defrosting, say, once every 24 hours of real time, it'll defrost once per 24 hours of compressor run time, saving a whole lot of energy in winter, spring and fall, in the summer in moderate climates, and in air-conditioned houses.

I did some looking at defrost timers and they are listed by hours of run time/minutes of defrost time. The longest I think I saw was a 16/35 but more commonly they seem to use 10/21 these days but the fridge I took out was 6/21. Considering the very high duty cycle of the compressor (it was wired as you suggest) the thing ran a defrost cycle at least twice a day if not three times. Then the refrigeration has to catch up to remove the heat that the heater just dumped into it. The frost buildup was very low when this happened and I was toying with trying to change it but I didn't think that was the major energy wasting part, more likely just the refrigeration itself.

The new one has an Adaptive Control (Whirlpool) which apparently senses how long it took the defrost termination switch to open on the last cycle and times the next one accordingly. It seems to settle on about 24 hours of total time in my case and fills the drain pan about halfway, much more water and less often than the old one did.

If anybody has insider information on how the Whirlpool ADC works I would be curious to know that too. The Samurai appliance repair man site seems to think these fail a bit too often so my current thought is to replace it with a regular timer if it ever breaks.

Birken

[mike1000001]

The new freezer you have probably has a smaller compressor, but I can't say for sure since I've seen some very small compressors on old models. The manual defrost freezers are very efficiant by design since the only thing drawing power is the compressor (no fan motors or anything else) and the frost build up on the evaporator (the shelfs) will help in maintaining a temperature when the door is opened for a short period. Having the freezer packed full will also help with energy efficiancy for the same reason. the biggest problems with the manual defrost freezers is the condensor coilsealed within the wall of the freezer. With a very hot ambient temperature they don't work near as well or as efficiantly as a rear mounted static condensor or especially one with forced air cooling.


About the Adaptive Defrost Control on your Whirlpool, the control seperates the defrost cycles apart so it can target an 11 minute heater on time untill the defrost termination thermostat shuts it off. if its taking 9 minutes untill the thermostat opens, it will space the defrost cycles out furher. If its longer then 11 minutes it will put them closer together. Every Whirlpool side by side, and refrigerators built on that same chassis, with the ADC system seem to defrost at 24 hour intervals no matter how they are used. Doesn't matter if there is 10 people in the house or just one, they all seem to do it at 24 hours. At least on all the ones I've had a temp-scribe in for long enoufgh to see the defrost cycles.
And the defrost cycles it times out to adapt, it bases it off the last 30 defrost cycles so having the heater run for 20 minutes or longer for a few days in a row won't do anything to change the defrost interval as long as if after that it goes back to its normal time.

Most all other manufacturers do it the same way as Whirlpool with the ADC system with the exception of GE. Their refrigerators have a thermistor mounted on the top of the evaporator that can measure the frost build up and it defrosts when needed. Neat idea but its not near as reliable as the Whirlpool system. Sure they do fail, but its pretty rare. I would even say the old mechanical timers fail 10 times as much as the Whirlpool ADC. Now if you're talking about the Maytag side by sides before they started using the Amana chassis, those fail like nothing else. Back in the prime I would replace 3 a week, now that they are getting older and Maytag has never built a refrigerator to last so a lot of them are not being repaired I'm down to about one every3 weeks or so.

I've even put the Whirlpool ADC boards in refrigerators that had a timer just for the fun of it. It plugs right in to the standard plug (provided its wired the same as the Whirlpool ) and all you have to do is run two extra wires to it.
If you want to get more effiancy out of your old refrigerator you can put in a slower timer, or rewire your current times so the motor only advances when the thermostat cycles on. If it doesn't have the exposed motor wires, for $8 you can get a universal times with disconnected wires that you hook up to whatever terminal you want. Be careful though because every once in a while I'll run in to one that won't work that way unless you do some rewireing. Usually because the timer motor neturals itself through another circuit and for one reason or another it stalls out in defrost if whatever is in that circuit opens the connection up.
If your refrigerator has a horizontal evaporator just leave the defrost timer alone as they usually need to defrost that often to keep the evaporator clean.

[Rick M]

If you really want to see what your appliance is burning get a kill-a-watt meter P3 - Kill A Watt

Got one off of eBay. They are interesting to mess with and great for figuring generator load on 120v circuits.